Here's my summary of the video that ExGingi and Yehuda57 posted, which can also be seen here:
https://covid19ch.blogspot.com/2021/01/covid-vaccine-q-with-dr-eli-rosen-and.htmlIt's really worthwhile to listen to the video, but because some are unable to do that, I've summarized it here. In a few places I quoted Dr. Bar-Zev directly. My apologies if I misrepresented anything.
Dr Eli Rosen, physician of Crown Heights, interviews Dr. Naor Bar-Zev, MD pediatrician and PhD in epidemiology of infectious diseases. Dr. Bar-Zev has conducted research on vaccination around the world, including Africa, Southeast Asia, the Pacific, and Malawi. He’s on the faculty of Johns Hopkins University, and has been involved in planning related to the Covid vaccine
Some people are saying that the vaccine is 95% effective. What does this mean?We should say that the vaccine has 95% efficacy, not 95% effectiveness, because vaccine experts use these words differently. Efficacy describes how much disease is prevented by the vaccine in a clinical trial, and effectiveness describes how much disease is prevented after the clinical trial, when the vaccine is given to people in the real world.
Often, a vaccine that works well in a clinical trial ends up working a bit less well when given to the general population, for two reasons. First, compared to the people studied in the clinical trial, the general population is more varied, with people who differ in obesity, health conditions, medications they’re taking, and so on. Because of this, the effectiveness might be a bit lower than 95%. Secondly, stuff happens when vaccines are given to millions of people, so perhaps the vaccine is not kept at the proper temperature (although tremendous effort is being exerted to prevent that), and that might decrease its effectiveness. Based on experience thus far, we expect the vaccine’s effectiveness to be close to its efficacy, but nobody can honestly say yet what the effectiveness will be until more time has passed.
Does the vaccine protect us from getting sick, and also from infecting others?Let’s define a few terms:
Colonizaton: Germs, such as bacteria and viruses, make their homes on us. They cause no problem, or even make us healthier, such as the bacteria that colonize our skin and our gut.
Infection: Germs enter our body in a place where they shouldn’t be.
Disease: The infection caused by the germs produces symptoms of illness.
Having the disease Covid-19 means we were previous infected by SARS-COV-2. But having a SARS-COV-2 infection does not mean that we will necessarily develop Covid-19. It’s possible to have an infection, but no symptoms occur, so the person doesn’t even realize that they’re infected. This is called asymptomatic infection and is very common with the SARS-COV-2 virus.
It’s important to realize that people who are infected but have no symptoms are able to transmit the virus to someone else, and that’s why we’re asked to use masks and distancing even when we feel 100% fine. We might have an asymptomatic infection, that leaves us feeling fine, but allows us to unintentionally transmit the virus to others. The CDC estimates that probably about half of all transmissions in the community are occurring from people without symptoms.
The clinical trial was designed to see if the vaccine could prevent disease, not to see if it prevents asymptomatic infection. This made sense, because we were in the midst of a pandemic, and preventing disease was paramount. But it means we’re only able to conclude that the vaccine greatly lowers your risk of getting Covid. We can’t conclude that it lowers your risk of getting an asymptomatic infection, and thereby being able to infect others.
Now, this doesn’t mean that the vaccine doesn’t prevent asymptomatic infection and transmission, just that we don’t yet know. Pfizer did find that when animals were studied, their vaccine did decrease transmission, but AstraZeneca’s vaccine (not the same kind as Pfizer’s) did not show great reductions in transmission. All we can say at this point, is that we don’t know whether or not the vaccines will prevent asymptomatic infection and transmission.
But keep in mind that this is also true of those who get Covid naturally. We know that those who recover from Covid are protected for three months, possibly longer, but we don’t know whether those people could get a second infection, this time asymptomatically, and subsequently infect others. In fact, a study just came that suggests that that is does happen.
COVID reinfections are unusual — but could still help the virus to spread So even if we’re vaccinated, we still need to wear a mask and socially distance so that we don’t unknowingly transmit the virus to someone else.
Can children carry and transmit the disease?Very young children are at much lower risk of disease, and even when infected, they’re usually asymptomatic. They are also slightly less likely to transmit the disease -both because they’re less likely to be infected in the first place, and also because their cells have fewer ACE-receptors, which is the protein the virus uses to enter the cell.
But although a child is less likely to get infected than an adult, when children are in overcrowded conditions, such as may occur in a yeshiva or cheder, their chance of getting infected increases, which is why they need to implement social distancing and other protective measures.
Older adolescents and young adults in their 20s, are the major transmitters of disease in the community, often when they themselves remain asymptomatic.
Do we know which part of the immune system is affected by the vaccine?Generally, when we speak of how a vaccine induces an immune response, we refer to the production of antibodies. When a virus infects us, a range of different antibodies are produced to different parts of that virus. Only some of these antibodies will be neutralizing antibodies, that is, antibodies that prevent the virus from attaching to our cells, and the earlier parts of the clinical study (Phase 2) did find that the vaccine stimulates production of these neutralizing antibodies, produced by B cells.
The vaccine (and natural infection) also stimulates production of another group of cells, T cells, which also fight infection. In addition to the active B and T cells, a group of memory B and T cells are produced, which hang around for a long time. They retain the memory of this virus, and when we encounter it again, these memory cells rapidly kick into action, and we fight off the infection before we even develop symptoms. Some of the vaccine trials did look for and find memory T cells, which reassures us that there’s a very good chance that the T-cell response to the vaccine will be long-lived.
With measles, we have found a certain level of antibodies provides protection from infection, but we don’t yet have that knowledge for SARS COV-2. We had hoped we might get information on this during the clinical trials, but we didn’t. So we can’t measure our antibodies to know whether we’re protected.
A side point to keep in mind is that after you’re vaccinated, you will have antibodies in your blood. Until now, we’ve been measuring antibody levels to figure out whether someone had a past infection, but in the future, a positive antibody test could be the result of either past infection or vaccination.
If the vaccine works, do we still need to wear a mask and socially distance?Yes. We still need to maintain all the normal precautions. We can be happy that we’ve received the vaccine, and are protected ourselves, but we don’t yet know whether we can still develop asymptomatic infection and transmit that virus to others.
Is it true that the new administration is planning to advocate for omitting or delaying the second dose, and what are the risks and benefits of that?No, that is a misunderstanding. Nobody is advocating for giving only one dose of a two-dose vaccine. The first dose gives you only about 50% immunity, and you really need both doses to get the 95% efficacy.
For the current two-dose vaccines, the question is not if, but when, the second dose should be given. This is because of the way the body builds up its production of antibodies. After meeting a viral protein, B cells are stimulate to proliferate and produce lots more B cells. As this proliferation occurs, the B cells are also undergoing a maturation process, such that as time goes on, they become more and more expert at producing the antibody to perfectly neutralize this particular virus. If the second vaccine is given soon after the first, the B cells aren’t mature enough to know how to respond. On the other hand, we don’t want to wait a long time before given the second dose, because the person won’t have optimal immunity, and we’re in the middle of a pandemic. How long can we wait? In the AstraZeneca trial, sometimes it happened that the second dose was given with a delay of 6 weeks, and it didn’t seem worse than giving it earlier. So there’s been some discussion to postpone the second dose in the Pfizer and Moderna vaccines, so that more people could get the first dose soon, and give the factories time to make more vaccine for the second dose. This is a reasonable debate to have.
There is a one-dose vaccine in development by Johnson & Johnson. Will this one-dose vaccine have the same high efficacy as the 2-dose vaccines of Pfizer and Moderna? Will it induce immunity that lasts as long? Will it work as well for the elderly, whose immune system is slightly less responsive? It’ll be a few weeks before we get results of their clinical trials, and see if their vaccine wins Emergency Use Approval.
How long will immunity last after the vaccine?Obviously, we don’t know, because we haven’t had enough time since the beginning of these trials. The clinical trials started around June/July, and some people had been followed for two months at which time Pfizer announced their results. If you now add November, December, January, we can say that those people who were vaccinated first have had immunity for 5-6 months.
The trials were supposed to continue for two years, and scientifically, we would like to continue them for that long. But ethically this might not be possible, because now that the vaccine has proven to work, the people in the study who had gotten placebo might understandably want to get the vaccine. So we probably won’t learn about the longevity of immunity from the clinical trial, but we will learn about it from simply observing the large population of people who’ve been vaccinated, and seeing whether they start getting infected, though this will take a long time.
Will the vaccine be effective against the new strains of the virus we hear about?It’s natural for there to be changes in a virus over time, though not all variants are a health issue. Some of the recently emerging strains do seem to be more transmissible, which is of concern, but fortunately they don’t seem to cause more severe disease. However, it is possible that a future strain might arise that doesn’t respond to our current treatments, or that may be able to cause disease in those with immunity from a previous Covid infection, or from our current vaccine. These possibilities are being actively studied, and so far, the results are reassuring that our vaccines will work against the UK and Brazil strains. But we need to remain vigilant, and scientists are studying the genome of SARS-CoV-2 viruses around the world, so as to be alert to the emergence of dangerous variants. It’s likely that at some point we’ll need to develop a slightly different vaccine. This isn’t unexpected; it happens all the time in vaccinology.
Is the vaccine safe?This question is of utmost importance. You should realize that vaccine safety is paramount. First of all, Dr. Bar-Zev says that he takes safety seriously for personal reasons; he would not want to give his children and his elderly parents anything unsafe. Also, he’s in the business of making vaccines available globally, and an unsafe Covid vaccine would cause people to distrust all vaccines. And vaccines are given to healthy people, to keep them from getting sick, so we don’t want to give a healthy person a vaccine that would cause symptoms that are worse than the disease itself. For all these reasons, he takes this topic very seriously.
mRNA vaccines are not totally new; they’ve been studied for 20 years, since the SARS outbreak in 2003. So there is actually considerable evidence that this kind of vaccine is safe in general. In addition, the clinical trials on the Covid vaccine were actually much larger than usual. For typical vaccine trials, we would study 1500- 10,000 people for 10 or 15 years until enough people developed the disease and we could calculate vaccine efficacy. But with Covid, each trial studied 30-40,000 people, and Covid was very prevalent, so enough cases occurred in just two months. So even though it was called “warp speed”, you shouldn’t think that corners were cut. It’s just that less time was needed because of the high rate of SARS-CoV-2 prevalence and the very large number of people who participated in the trial.
With regard to short-term safety, we have lots of data. Besides the 30-40,000 people in the clinical trial, there are now millions of people who’ve taken the vaccine, so we have very good information on the short-term side effects. The Covid vaccine does cause local side effects that are not very pleasant, particularly after the second dose. People should expect to have pain or redness or a little bit of swelling. They may have a fever, muscle ache, and feel unwell for a day or two, maybe even three. People should be prepared for this, so if you need help with your shopping, for example, you should prepare in advance. These effects aren’t trivial, but they’re common, and should be expected to occur.
No vaccine is 100% safe, and serious side effects can occur. These may be so rare that they don’t show up in a trial of 40,000, because they affect only one in a few million. Even though these are highly unusual, they need to be reported. Some of these rare events may be coincidental. That is, if someone gets the vaccine and has a stroke the next day. Did he have a condition that made it likely that he would be one of the thousands of people who have a stroke every day? Or was the stroke related to the vaccine? When physicians report these rare events, we can monitor this and study whether the vaccine seems to be causing this problem. It’s very important not to be dismissive and to be humble and to really diligently look into this sort of information, because we owe a duty to tell the public if there is a risk of one in ten thousand, or one in a million, of some side effect. The systems in the US for monitoring these events has been strengthened, and the WHO is establishing worldwide surveillance as well.
What about long-term effects? Can the vaccine cause problems 20 years from now?There are things we just can’t know until 20 years go by, so there certainly will be studies in the future that look at whether the vaccine is associated with some condition, though there’s no reason to expect this.
When we think about risk of taking the vaccine, we have to also consider the risk of not taking it. Yes, there are risks of the vaccine, and some of them will be serious, though very rare. But there are risks to the disease too, and the disease is severe in older adults and those with underlying conditions. In older people, certainly the risk of disease is much greater than the risk of vaccine, and it’s clear that they should vaccinate. But even with younger people, the disease can be risky, and intensive care physicians will tell you they’ve got a 32-year old on a ventilator. So the risk of disease is greater than the risk of the vaccine in young adults, too, and the evidence is in favor of vaccination. The case of children is still unknown.
What about pregnant women?Pregnant women weren’t in the original clinical trials, but they are being recruited now for clinical trials. We know that women who get Covid while pregnant have some increased risk, though not as great as those who get the flu. Pfizer and Moderna studied their vaccine in pregnant animals, and it didn’t cause any major problem. So what should we do for women who are pregnant now, before we have the results of clinical trials? The current recommendation in the US is that if a woman is pregnant and is at greater risk, either because of an underlying medical condition or because she works in health care, then they can get the vaccine, but it’s still recommended that she discuss her particular case with her personal physician.
For women who are breastfeeding, Dr. Bar-Zev doesn’t see any problem with the vaccine. Although they haven’t been in clinical trials, he feels that based on his knowledge as an immunologist, a vaccine scientist, and a pediatrician, they should get the vaccine.
What about fertility?For women who are undergoing fertility treatment, on IVF, there’s nothing known. Some doctors say not to get the vaccine, because it can cause a fever, which may be a problem during fertility treatment, so a woman should speak to her gynecologist or obstetrician of family physician. It’s a personal issue, so don’t just look at general guidance but discuss it with your personal doctor. Dr. Bar-Zev doesn’t know enough to say more about that.
A second issue that’s been circulating in our community and on social media is the concern that the vaccine will affect fertility. The concern is that antibodies to SARS-CoV-2 might also attack syncitin, a protein that’s involved in the placenta, and thereby damage the placenta in future pregnancies. This is obviously a frightening possibility, especially in our community where fertility is such an important part of our life. But the facts are as follows: There is no similarity between syncitin and the part of SARS-CoV-2 where the antibody attaches, so it’s unlikely that the antibody would affect this other protein. In addition, there have been millions of women who got Covid, and we haven’t seen a drop in fertility. So this idea doesn’t make sense biologically, and isn’t supported by what’s happening in reality.
Autoimmune diseaseSome people with autoimmune diseases, such as Crohn’s disease or juvenile rheumatoid arthritis are taking monoclonal antibodies for their disease. There is no problem with them taking the vaccine.
If you had monoclonal antibodies as part of the treatment for Covid, then you should wait three months and speak to your physician before taking the vaccine.
Can the vaccine induce autoimmunity? This claim is often raised by those who oppose vaccination, and it’s not 100% false, but it’s been hyped up way more than it deserves to be. It is certainly biologically possible, but it seems to be extremely rare. There was one case reported recently of a young obstetrician who developed thrombocytopenia soon after vaccination. This condition means the blood doesn’t clot normally, and he sadly developed a massive stroke and died. It’s possible that this was coincidental, but it’s also possible that it was caused by the vaccine, and if so, it might be through an autoimmune mechanism. But it is extremely rare, and is the only case out of millions of doses that have been given. We need to be on the lookout for other such cases, but at this point, they are so very rare that it is not likely to be a major issue, and not anywhere near the risk of getting Covid.
What about the specific components of the vaccine?With regard to the mRNA itself, there is no safety issue. It breaks down very quickly, so isn’t around to cause long-term damage. In fact, a concern with the mRNA vaccine is that the mRNA might break down soon after leaving the factory, and it’s maintained at super cold temperatures to prevent that.
The mRNA is further protected by being enclosed in a tiny fat bubble made of a type of cholesterol. This kind of cholesterol is a common chemical in our body, so no problem with it.
There’s no adjuvant, no egg, no latex, no gelatin, no preservatives, no mercury, no alum. Those things are not necessarily unsafe, but the point is that we don’t have to worry about them because they are not found in this vaccine, which is very simple.
Besides the mRNA and cholesterol, there is polyethylene glycol, and it’s possible that some of the very rare cases of severe allergy might have been caused by the polyethylene glycol.
It contains some sucrose, which is just table sugar, and sodium chloride, which is just salt, and potassium chloride, which is just another kind of salt, sometimes used in our food, and buffers made of sodium phosphate and potassium phosphate, which are part of our body anyway.
If I was previously severely ill with Covid, will the vaccine do the same thing, and perhaps cause a cytokine storm?This was actively looked for in the clinical trials, and the vaccine was not found to cause a cytokine storm. And the type of T cells that were induced by the vaccine, are the type that dampen down cytokine storms, so this reassures us that cytokine storms are unlikely. There was one such case reported in Israel last week, and reported to the WHO, and we’re monitoring to be sure, but based on millions of doses given, we don’t think this is a concern. Can I get Covid a second time, and is a cytokine storm more likely then? Or if I have a vaccine and still get Covid, am I at more risk of severe disease? We are looking into those questions, but all the indications so far are very reassuring.
Should people with a history of allergies be getting the vaccine?Severe allergic responses have occurred, but they are very rare. If somebody has an allergy to the first dose, they should speak to their physician before taking the second. If somebody has allergies to food it’s good to discuss it with your physician. It’s not a reason to not take the vaccine, but if you’re worried, perhaps your physician would want you to get the vaccine in a setting where equipment is available to treat a severe allergic response.
Some doctors say that the vaccine causes harm. Is it one person’s word against another?"I don’t want to get into loshon hara, and I don’t want to get into anything that might sound disrespectful to anybody. But I’ll just say the following comments. When I teach clinically, at the bedside, I always teach my trainees to never trust what anybody else says, and the person they should mistrust most of all is themselves. You always have to ask what if I’m wrong? The stakes are so high. What have I not thought of? What harm might come to my patient because of being rash, or being overconfident, or being arrogant, or not listening to somebody else’s concern? That’s a fundamental issue in good clinical care, and it’s a fundamental issue in science and the conduct of science and particularly when it comes to populations of the magnitude that we’re talking about here. Even extremely rare events become important because you’re talking about a large scale, so the responsibility is to be humble and the way we approach this needs to be with humility and we need to listen to our detractors and to listen to people who disagree with us. The halacha is like Beit Hillel because they said the words of Beit Shammai first. And the same thing applies here. It’s superimportant in vaccinology and all science we listen to people who disagree with us. We want that rigorous oversight. I want people to not believe me. I don’t want to believe me. I want to be able to look at the methods with diligence and care, to see that they’re valid, repeatable, conducted in a rigorous way, and result in the outcomes that matter. I hold my opinion temporarily until I’m disproven and better science is developed. We never have access to the truth in science. It’s not emmes. We have temporary hypotheses that we try to disprove and as long as they withstand that scrutiny then that's okay and we go with that but the scrutiny is part and parcel of the science.
So I think it’s an important attitude to have. I’m not saying that I know anything better than anybody else, and I’m happy for people to disprove me because it will make me a better scientist and a better physician and a better human being and a better eved Hashem.
At the same time, unlike the Beit Shammai/Beit Hillel example, this isn’t really a question of elu v’elu. There’s a metzius and there’s a reality and a scientific approach to it. As long as people take a scientific approach, we have what to discuss. If they are strange theories, okay, that’s fine. People can think what they want. But people need to be able to distinguish science from fiction."
Can the virus change your DNA?No. It’s got nothing to do with DNA, which is in the nucleus. It doesn’t even last long enough in the cell to get to the nucleus.
What do you say to all the claims that the government has ulterior motives with regard to a vaccination, or all the talk about microchips?Dr Bar-Zev: No. I mean, I know these people, in the industry, in foundations… I know what drives them, I know what they bring up in conversation, I what worries them, I know what they lose sleep over, I know what they think is the right thing to do, and I know how evidence-based they are. And there isn’t any truth to this story of conspiracy theories and so on. And there are good and solid yidden in those foundations that worry about other yidden and indeed the broader community and the world… These conspiracy theories are just false. It’s just not true.
Is the vaccine really necessary, now that we have good treatments for Covid, like monoclonal antibodies?Prevention is better than cure. The treatments are not perfect, and sometimes work only at certain stages of disease. Clearly it’s better to prevent disease.
A person might say, I’m young and healthy, so I’ll be fine if I get Covid, why take the risk of an unknown vaccine? There’s some truth in that, in that everyone must weigh the risks for themselves, and these risks do differ by age. The risk of Covid is greater for older adults, and for them, there’s no question they should take the vaccine. But younger people are mistaken if they think they’re not at all at risk. We’ve seen many people 20-35 years old, who had severe disease and even were niftar. So the risk for an individual young person is low, but when we look at the whole population, the risk is high enough that we’re seeing these cases, and they’re preventable deaths, preventable by the vaccine.
If I had Covid and I have antibodies do I still need to get vaccinated? And if so, do I need two doses? There’s a lot of variability in response to a natural Covid infection. Those with very mild disease may have produced only a weak immune response. Those with more serious disease may have produced a better immune response, but in both cases, the response will wane over time, so it makes sense to give a second exposure to the protein that stimulates the immune response. Not a second exposure to the virus, but to the viral protein that’s occurs after getting the vaccine.
The two-part vaccine is called a prime-boost regimen; the first dose primes the immune system, and the second dose boosts the response. Sort of like learning, where you learn something, and start to forget it, but if you review, you will retain it much better. So if you had Covid, you should be vaccinated to help retain the immune response. Do you really need two doses, or is one enough? The answer is that hasn’t been studied, so we really can’t answer that. Perhaps taking only one dose would make sense, as a way to save doses for others. But what we do know is that two doses work. There’s no reason to think that those who had Covid would differ from the rest of the population, or that they would have less immune response, or get more sick, or have more side effects. All those are possible, but we just don’t have evidence. If you’re back to good health, you could get the vaccine, even if you still have antibodies, as these are expected to wane over time. But speak to your personal physician.
Final thoughts?“HKBH makes the refuah before the machalah. We have this kind of example to borrow, k’viyachol, histakel b’oraisa uvara alma. We’ve got this novel technology, which the body looks at, it reads the code and it produces this protein, in a way that’s really a testament to the miracle of the briya. It’s the work of the Aibishter in all of this, and we should be just thankful with shevach v’hodaya to HKBH that we have this capacity in this day and age to have a mageifa of this magnitude, and within less than a year have the capacity to curtail it because of where we are, and the learning that we have, and the technology we have. That’s a bracha, and we shouldn’t turn our backs to that bracha. We should use that bracha. We had a year of a terrible pandemic, for yiras Hashem, and we need to turn it now to ahavas Hashem, and really appreciate the brachos that we’re given.”
